Gives access to PC DOS and Windows 95 long filename format diskettes on BBC series

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A background

The internet has opened up a wealth of archived BBC software which can be downloaded at no charge. However, being able to transfer this software to the machine presents a serious problem because of the need to jump the gap from the PC to BBC micro.

The DOSFS ROM solves this problem by allowing the BBC micro to read and write PC format floppy discs including those from PCs running Windows which permits much longer filenames.

So what's required?

The filing system requires that the machine be fitted with either a 1770 or 1772 disc controller (eg.BBC Master and BBC B+) or disc upgrade kit (eg.BBC B) to work.

The drive must be capable of double sided accesses and be switched to 80 track mode if there is an option between 40 and 80 track as it uses double stepping to emulate 40 track drives. Normal 3.5" drives from PC suppliers are all 80 track by default.

Diskettes can be either single or double density (this is 360k or 720k in DOS terminology) formatted with 9 sectors per track, either 5.25" or 3.5" in size.

DOS filing system
DOSFS can be used with 3½" and 5¼" media

The ROM is supplied with a printed user manual including details of fitting the ROM for BBC B, BBC B+, and Master series with no soldering required.

Commands added

In addition to the normal filing system commands

there are built in commands to format and verify discs on your BBC Microcomputer

Machine: Command: Purpose:
BBC Micro*CLOSECloses all files
BBC Master*EX <dir>Examine the given directory
All*FORM 720 <drive>Formats the specified drive to 720k
All*FORM 360 <drive>Formats the specified drive to 360k
All*VERIFY <drive>Verifies all sectors on the specified drive


How do I tell whether my BBC B has a 1770 or 1772 disc interface already?
Look at IC78, immediately north of the keyboard ribbon cable. If it has a 40 pin chip in it, you have an 8271 controller and will need to upgrade. If it has a small circuit board on stilts then you have a suitable controller already.

My BBC B doesn't have a 1770 or 1772 disc interface, can I still use DOSFS?
Not directly, you'll need to change the disc controller for a 1770 or 1772 type as the one which was fitted to BBC B's normally can't handle DOS format discs. It's a simple upgrade to make and involves unplugging some chips from the computer and installing a small circuit board (no soldering required). This hardware upgrade is available separately from the same author.

The DOSFS ROM works with any Acorn compatible upgrade (the Opus 1770 upgrade and some early Solidisk upgrades are not compatible for example). Remember that both the BBC Model B+ and Master series already have a 1770 or 1772 fitted as standard.

What's the current version of DOSFS and how do I upgrade?
Currently, version 1.18. Users with earlier versions can upgrade by returning their ROM along with 3 first class postage stamps and your address details in a reusable padded envelope. You'll receive the latest version by return of post.

Can I use discs formatted under Windows too?
Yes, the DOSFS ROM includes a formatter and verifier but you can also use the one built into Windows. Note that Windows can read 360k formatted discs but doesn't offer this shape in the drop down list in the formatter, but you can achieve the same result from a DOS command prompt too

format /t:80 /n:9 A:formats as a 720k disc
format /t:40 /n:9 A:formats as a 360k disc
assuming that your floppy drive is 'A:' in this example.

What about compatibility?

Product: Compatibility:
Tube second processorsFine
Acorn 1770 DFS for B/B+Not compatible with version 2.0J, as it does not warn other ROMs in the machine that the filing system workspace is being claimed. Should upgrade to version 2.26.

DOSFS availability

Orders can be placed online, or alternatively sent by post.

Option: Price: Comments:
£15.00 inc postage
Includes printed user manual

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